Interfacial wave motion caused by wave-mud interaction

The generation of internal waves induced by surface wave in the fluid mud environment is examined via laboratory experiment in order to study its importance on surface damping. As wave propagates over soft muddy bottom, both viscous shear stress and interfacial motion contribute to energy dissipation. A fully developed fluid mud layer with a homogeneous concentration distribution is created to investigate the resulting energy dissipation for different wave heights, periods and mud densities. Visualization technique and wave gages were applied to measure interfacial motion and surface damping, respectively. Experimental results suggest that the induced interfacial amplitude depends mainly on the relative water depth, and the mode of internal oscillation was identified. Finally, based on the derived energy equation for two-layer system, we compare the relative importance of shear stress and mud motion.